Square wave to sine wave converter - Page 2 - Electronic Circuits Projects Diagrams Free

Leftyretro · 1st May 2008, 06:38 PM

Quote:

Originally Posted by Paul Obrien

A square wave can be thought of as a very large number of ODD hamonics added together (of course it really isn't) so if you build a low pass filter with the cut off well below the 1st odd harminic you will have the square wave convertor.

Correct logic but wrong term. There is no such thing as a 1st harmonic. There is the fundamental frequency, next comes the 2nd harmonic (an even harmonic), then the 3rd (an odd harmonic), etc.

I know it sounds wrong but harmonics are named starting with the 2nd

Lefty

**Nigel Goodwin** · 1st May 2008, 06:44 PM

Quote:

Originally Posted by Leftyretro

Correct logic but wrong term. There is no such thing as a 1st harmonic.

Actually you misread what he put, your quote clearly says "first ODD harmonic" - bit of a strange way to put it, but actually perfectly correct. Presumably English isn't his first language?.

deepika97 · 19th May 2008, 05:03 PM

Hi,

I am working with a feedback circuit for a sensor. I excite the sensor with a sinesodal voltage of aroung 50-200mV and 1K-500KHz. The output of this sensor is to read and so it is amplified. Now I need to put back the output voltage to 50-200mV since it is a feedback. I tried to use an AGC for this purpose but turned out to be real complicated for low amplitude signals. So I thought of using an diode clamping circuit to serve my purpose. But this gives a square wave of different harmonics. I need to convert this to a sine wave to avoid this. Can you suggest me any circuitry to serve my purpose. Can you also suggest any simple circuitry for AGC if any. Kindly do this help.

Regards,
Deepika

deepika97 · 20th May 2008, 07:15 PM

Hi Hero999,

I do not know your name and I apologize for addressing you using your username. You were talking about an AGC circuit if you want the amplitude to vary less. Can you suggest me an simple AGC circuit with couple of opamps, resistors and capacitors. I really need an AGC which can control my amplitude in the range of 10-100mV.

Regards,
Deepika

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19th May 2008, 05:03 PM	(permalink)
deepika97	reg:square wave to sine wave converter Hi, I am working with a feedback circuit for a sensor. I excite the sensor with a sinesodal voltage of aroung 50-200mV and 1K-500KHz. The output of this sensor is to read and so it is amplified. Now I need to put back the output voltage to 50-200mV since it is a feedback. I tried to use an AGC for this purpose but turned out to be real complicated for low amplitude signals. So I thought of using an diode clamping circuit to serve my purpose. But this gives a square wave of different harmonics. I need to convert this to a sine wave to avoid this. Can you suggest me any circuitry to serve my purpose. Can you also suggest any simple circuitry for AGC if any. Kindly do this help. Regards, Deepika

20th May 2008, 07:15 PM	(permalink)
deepika97	Hi Hero999, I do not know your name and I apologize for addressing you using your username. You were talking about an AGC circuit if you want the amplitude to vary less. Can you suggest me an simple AGC circuit with couple of opamps, resistors and capacitors. I really need an AGC which can control my amplitude in the range of 10-100mV. Regards, Deepika